Connective Tissue I

Question 1

describe fibroblasts

Answer 1

• Most common cell in connective tissue
• Synthesize fibers and ground substance
• Myofibroblasts: wound healing and presence of contractile filaments

Question 2

describe the 2 pictures

Answer 2

• top: adult fibroblasts
  
  • large oval nucleus
  • spindle shaped basophilic cytoplasm
  • active protein synthesis
• bottom: fibrocytes
  
  • collagen synthesis stops
  • lose basophilic cytoplasm
  • nucleus shrinks

Question 3

Answer 3

EM of fibroblasts

Collagen fibrils can be noted outside the cell

Question 4

describe brown fat

Answer 4

• many lipid droplets
• rich in mitochondria
• highly vascular
• main function: heat production

Question 5

describe macrophages

Answer 5

• derived from monocytes–migrate to connective tissue, differentiate to macrophages
• irregular cell membrane/cytoplasmic extensions (pseudopodia)
• phagocytic; produce cytokines
• antigen presenting cells; multinuclear giant cells

Question 6

Answer 6

• Macrophage
• prominent Golgi
• abundant lysosomes breakdown of phagocytic materials
• numerous phagocytic vesicles (or phagosomes) for the storage of ingested materials
• nucleus has an irregular outline

Question 7

describe mast cells

Answer 7

• originate in the bone marrow from precursor cells lacking cytoplasmic granules
• when they migrate to connective tissue or lamina propria of mucosae, they proliferate and accumulate cytoplasmic granules
• mast cells and basophils circulating in the blood are derived from the same progenitor in the bone marrow

Question 8

Answer 8

EM of mast cell

• granules containing histamine and heparin

Question 9

describe lymphocytes

Answer 9

• small, spherical cell with a scant cytoplasm
• condensed, basophilic nucleus
• immune cells – B and T cells
• B-lymphocytes develop into plasma cells

Question 10

Answer 10

lymphocytes

Question 11

describe plasma cells

Answer 11

• plasma cell is derived from the differentiation of B lymphocytes
• synthesizes and secretes single class of immunoglobin
  
  • immunoglobins are glycoproteins
• Basophilic cytoplasm (increased rER)

Question 12

Answer 12

plasma cells

Question 13

describe eosinophils

Answer 13

• eosinophilic (red) granules in the cytoplasm
• condensed, bi-lobed nucleus
• phagocytosis of antibody-antigen complexes

Question 14

Answer 14

eosinophils

Question 15

name the distribution of collagen

Answer 15

• Type I collagen
  
  • bone, tendon, dentin and skin
• Type II collagen
  
  • hyaline and elastic cartilage
• Type III collagen
  
  • reticular lamina of basement membrane as a component of reticular fibers
• Type IV collagen
  
  • basal lamina. Each molecule binds to binding site of laminin
• Type V collagen
  
  • aminon and chorion in the fetus, muscle and tendon sheaths
    ​

Question 16

describe reticular fibers

Answer 16

• type III collagen primarily
• short, thin and branching in nature
• found in organs with large volume changes
  
  • spleen, arteries, intestine, testes, etc.
• argryrophilic (silver staining) and PAS positive (due to carb content)
• first type of collagen synthesized during wound healing

Question 17

Answer 17

• loose (areolar) connective tissue
  
  • fills space between other tissues - large number of cells
  • flexible, rich blood supply, not resistant to stress

Question 18

Answer 18

• dense irregular connective tissue
  
  • fewer cells, more fibers than loose tissue
  • no orientation of collagen fibers – resistance to stress in all directions
  • organs capsules, periosteum, dermis

Question 19

Answer 19

• dense regular connective tissue
  
  • specific orientation of collagen fibers
  • tendons/ligaments
  • imparts tensile strength

Question 20

Answer 20

• reticular connective tissue
  
  • reticular cells (modified fibroblasts) – cytoplasmic extensions cover reticular fibers
  • frame work for myeloid (bone marrow) and lymphoid (lymph nodes, speen) organs

Question 21

Answer 21

• PAS staining of reticular connective tissues

Question 22

Answer 22

• elastic connective tissue
  
  • elastic fibers - yellow colored
  • ligamentum flavum, vocal ligament, suspensory ligament of penis

Question 23

Answer 23

• elastic stains highlights the large number of elastic fibers in aorta

Question 24

Answer 24

• white adipose cells
  
  • cells are large
  • nucleus is peripheral
  • lipid droplet is one
  • function is fat storage

Question 25

Answer 25

• brown adipose tissue
  
  • cells are smaller
  • nucleus is central
  • lipid droplet is many
  • function is energy release

Question 26

define hypertrophic scar

Answer 26

• scar when raised more than normal but within original wound boundary

Question 27

define keloid scar

Answer 27

• when in excess of boundary, extending into surrounding tissue